code: def get_missing():
      # Return None for missing keys. Can't be a lambda function if we want to use Pickle.
      return None
  
imports: import collections
  import logging
  from cellprofiler_core.constants.measurement import RESERVED_METADATA_KEYS, C_MONOCHROME, C_RGB, C_TILE, C_URL, C_SERIES, C_C, C_Z, C_T, C_INDEX, C_SERIES_NAME
  from cellprofiler_core.pipeline import ImageFile
label_desc: Use image node_id 1 for calling a global function with example usage: get_missing() and returns: None